As humans, most of us will only ever see first-hand, the planet Earth. While Earth is a beautiful, awe-striking planet, there are others in our solar system that neither we nor any future generation will see, that would leave us marvelling in the wonders of the galaxy. Unfortunately, the nature of most of these planets makes it currently impossible to visit them by spaceflight; though, one day, that may change.

Pluto

Pluto is the largest dwarf planet in the solar system and exists in the Kuiper Belt, and the 9th largest object orbiting the sun. The temperature on the planet averages at around -229 degrees Celsius and it is covered in rocks and ice. There was a debate, for a time, over whether Pluto could be classified as a planet due to the discovery of several other rocks of similar size in the same belt. It was reclassified as a dwarf planet in 2006 after the International Astronomical Union more formally defined the term ‘planet’ at their 26th General Assembly.

Mercury

Perhaps, the opposite of Pluto in its attributes, the temperature on Mercury moves between two extremes. During the day – which typically lasts around 58 Earth days – the sun can raise temperatures to as high as 427 degrees Celsius, while at night they plummet to -173 degrees Celsius. Mercury is also lacking an atmosphere, meaning that anyone that was ever to visit the planet would hear no sounds and smell no odours.

Venus

Venus is one planet with a very distinctive smell – the smell of decay. Venus is too hot for habitation, sometimes even surpassing Mercury’s temperatures due to a greenhouse effect that is caused by its extremely thick atmosphere (something that Mercury lost when the sun burned it away) and a walk on its surface would require an immense amount of human energy, for much the same reason. Venus is the 2nd planet from the Sun, just behind Mercury, and is the 2nd brightest thing in the sky during night aside from the Moon, and spins in the opposite direction to most planets.